Handle comparing with TypeVar in mergeRefinedOrApplied

DolphinChips · DolphinChips · commit 9b060ec20aab · 2025-05-07T09:11:45.000+03:00
Closes #23032
diff --git a/compiler/src/dotty/tools/dotc/core/TypeOps.scala b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
@@ -278,7 +278,15 @@ object TypeOps:
           }
         case AndType(tp11, tp12) =>
           mergeRefinedOrApplied(tp11, tp2) & mergeRefinedOrApplied(tp12, tp2)
-        case tp1: TypeParamRef if tp1 == tp2 => tp1
+        case tp1: TypeParamRef =>
+          tp2.stripTypeVar match
+            case tp2: TypeParamRef if tp1 == tp2 => tp1
+            case _ => fail
+        case tp1: TypeVar =>
+          tp2 match
+            case tp2: TypeVar if tp1 == tp2 => tp1
+            case tp2: TypeParamRef if tp1.stripTypeVar == tp2 => tp2
+            case _ => fail
         case _ => fail
       }
     }
diff --git a/tests/pos/i23032.scala b/tests/pos/i23032.scala
@@ -0,0 +1,2 @@
+def f[F[_], T, U]: F[T] | F[U] = ???
+def x = f.toString

Original file line number	Diff line number	Diff line change
`@@ -278,7 +278,15 @@ object TypeOps:`
`278`	`278`	`}`
`279`	`279`	`case AndType(tp11, tp12) =>`
`280`	`280`	`mergeRefinedOrApplied(tp11, tp2) & mergeRefinedOrApplied(tp12, tp2)`
`281`		`- case tp1: TypeParamRef if tp1 == tp2 => tp1`
	`281`	`+ case tp1: TypeParamRef =>`
	`282`	`+ tp2.stripTypeVar match`
	`283`	`+ case tp2: TypeParamRef if tp1 == tp2 => tp1`
	`284`	`+ case _ => fail`
	`285`	`+ case tp1: TypeVar =>`
	`286`	`+ tp2 match`
	`287`	`+ case tp2: TypeVar if tp1 == tp2 => tp1`
	`288`	`+ case tp2: TypeParamRef if tp1.stripTypeVar == tp2 => tp2`
	`289`	`+ case _ => fail`
`282`	`290`	`case _ => fail`
`283`	`291`	`}`
`284`	`292`	`}`